Network interfaces generally provide data packet transfer capabilities between a network and a host system. The host system may employ a driver circuit between the network interface and the operating system (or a user program or a system call performing an operation in the user's context) that produces and consumes the data packets. The network interfaces typically generates an interrupt to the driver circuit to signal a condition that may require the attention of the driver circuit, for example the completion of a data transfer and/or the availability of new packets. Interrupt processing is relatively computationally expensive, however, and consumes processor cycles that could have been used for other purposes. In particular, interrupt handling may increase network processing latency since it diverts the CPU in the midst of performing other tasks. A system that reduces the frequency of generated interrupts may therefore be advantageous. Attempts to reduce the number of generated interrupts, however, must not result in a loss of any interrupts as this would cause operational problems for the system.
Furthermore, network stack processing in the driver circuit often introduces additional latency in the transfer of packets between the network interface and user applications because the network stack processing is typically designed for higher throughput rather than lower latency. Some attempts to improve performance by sharing queue access between network stack processing and user context applications may result in synchronization problems. These conflicts may arise between the multiple user context system calls, acting on behalf of the user applications, and the network driver circuit, each of which may simultaneously attempt to access the network interface queues.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art.